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(No Model.) 2 Sheets-Sheet 1,

S. BERGMANN.

TELEPHONE.

No. 440,096. Patented Nov. 4, 1890.

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(No Model.) 2 Sheets-Sheet 2.

S. BERGMANN.

TELEPHONE.

No. 440,096. Patented Nov. 4, 1890.

ATTEQL I INVENTOR:

NITED STATES PATENT OFFICE.

SIGMUND BERGMANN, OF NEW YORK, N. Y.

TELEPHONE.

SPECIFICATION forming part of Letters Patent No. 440,096, dated November4, 1890.

Application filed February 28, 1884. Serial No. 122,320. (No model.)

To all whom it may concern.-

Be it known that I, SIGMUND BERGMANN, of New York city, in the countyand State of New York, have invented a certain new and usefulImprovement in Telephones, of which the following is a specification.

This invention relates especially to telephone-receivers of that classwherein a movement of the diaphragm is produced by the expansion andcontraction of the constantlytouching electrodes caused by the thermaleffect of the current at the junctions of said electrodes.

In carrying out my invention I employ two or more electrodes of suchcharacter as to be readily afiected thermally by the current. Oneelectrode is attached to the diaphragm, and they are all so arrangedthat they may be adjusted to loose contact. Preferably I employ a numberof cylindrical buttons, composed of or faced with tellurium, placedtogether in a tube of insulating material, means being provided foradjusting them in the tube to the proper degree of loose contact. Thecurrent passes through the series of electrodes, and at the contactsvariations in expansion or contraction of the tellurium are produced bythe variations of the current transmitted to the instrument. Vibrationsof the diaphragm corresponding to such current vibrations are thusproduced. I may, in order to produce an increased eifect, employ meansadditional to the current required for operating the instrument forheating the electrodes, keeping them at a constant normal point ofexpansion, so that the current variations produce changes above andbelow this point. These extra heating means may be a battery in theline, or a coil from the transmitter-battery at that end of the line, orfrom a separate battery may be wound around the tube inclosing thecontact-buttons. This lamp may form the only source of heat while theline is not in use, or a battery, such as shown at G in Fig. 6, may becontinuously in the circuit as an additional source of heat, or heat maybe applied by means of an alcohol or other flame, or in any otherconvenient manner. This extra heating is applicable not only to myparticular form of receiver, but to any which employ the thermal efiectof the current and to thermally-afiected transmitters as well.

In the accompanying drawings, Figure 1 is a side elevation of a receiverembodying my invention; Fig. 2, a sectional view of the same; Fig. 3, arear elevation; Fig. 4, a section of a modified arrangement of theadjusting devices; Fig. 5, a view of a contact-button faced withtellurium, and Figs. 6, 7, and 8 are diagrams illustrating differentways of heating the receiver.

A is a suitable case provided with an earpiece B and holding thediaphragm O, which in this instance is of metal. Circuit-wire 1 isconnected with the diaphragm. Attached to the center of the diaphragm isthe conducting-rod a. This is attached to or bears against the first ofthe series of cylindrical contact-buttons b b, which are of tellurium orother readily thermally-aifected conducting material, or may be of anyconducting material 0, Fig. 6, faced with the tellurium d d. The buttonshave their .meeting surfaces planed smooth, so that they are in cont-acton the whole of such surfaces. The series of contact-buttons is inclosedin a glass tube 6.

Adjusting means for the buttons are provided, supported by the metalbridge-piece D, joined to the case A by the insulating-posts E E. Astationary sleeve f is held in the center of the bridge-piece D, throughwhich passes a rod g, having a rib h, which enters a slot in theinterior of the sleeve, so that the rod can move longitudinally butcannot turn within the sleeve. Upon the inner end of rod g is a metalsleeve 2', whose closed end bears against the end of the tube and thelast button, Fig. 2, of the series. Near its outer end the sleeve f isinternally screw-threaded, and a thumb-screw It turns within said sleeveupon the rod g and against the enlarged portion of said rod, thethumb-screw being held to the rod 9 by a screw it. It is evident thatwhen the screw kis turned the rod 9 and sleeve iare moved forwardagainst the inclosing-tube and the contact-buttons, and the tube will bemoved thereby, while the buttons, being pressed by a, are pressed intoclose contact. The circuit-wire 2 is connected with bridgepiece D, andthence with the electrodes.

In the form shown in Fig. 4 a spring Z is placed within the tube, andthe sleeve 1 bears against said spring, the other end of which isattached to a sliding block m, Which is in contact with the last buttonof the series.

The pressure of the spring and consequently the contact of the buttonsis adjustable in the same manner as in Fig. 1.

As previously explained, the buttons are adjusted to loose contactsthroughout the series. Then variations in temperature, caused byvariations in the current from any suitable transmitter Which passesthrough the series of electrodes, cause variations in expansion andcontraction at the contact-surfaces of the buttons, and consequentmovements of diaphragm by Which the sound- Waves imparted to thetransmitter are reproduced.

To produce an increased effect, as before explained, means are providedfor raising the contacts to a certain normal heat, the current causingvariations above and below this.

Referring to Figs. 6, 7, and 8,R is the thermally-affected receiver; T,any suitable transmitter; G, the transmittenbattery; I, theinduction-coil, and L the line.

In Fig. 6 an extra battery G isplaced in the line, and the currenttherefrom heats the contacts of the receiver.

In Fig. '7 a coil 0 is formed around the tube inclosing thecontact-buttons, such coil forming partof an extra circuit from thetransmitter-battery G.

In Fig. 8 a lamp H is used to heat the tube and contact-buttons.

It is evident that the tube for holding the electrodes may be used forsupporting the electrodes or contacts of any telephone Whose electrodesit is desired to adjust to or from each other.

What I claim is 1. A thermal telephone comprising the combination of avibrating sound-reproducing body, two or more electrodes sensitive toheat making end contact With each other, and a tube inclosing-saidelectrodes and supporting them in proximity to the Vibrating body,whereby the expansion and contraction of said electrodes move thesound-reproducing body, substantially as described.

2. A thermal telephone comprising the combinationof a vibratorysound-reproducing body, two or more electrodes sensitive to heat makingend contact with each other, a tube in closing the same, and means foradjusting said electrodes in said tube, whereby the expansion andcontraction of the electrodes move the sound-reproducing body,substantially as described.

3. In atelephone-receiver, the combination, with a diaphragm, of aseries of electrodes of metal readily affected by heat, such astellurium, situated in loose contact with one 'another, substantially asset forth.

4.. In a telephone-receiver, the combination of a diaphragm, a series ofcontact-buttons of a material, such as tellurium, readily affected byheat, one of said contact-buttons being connected With the diaphragm, atube inclosing the contact-buttons, and means for adjusting said buttonsWithin the tube, substantially as set forth.

5. The combination, with a telephone operated by the heating effects ofthe electric current, of an additional source of heat applied to theelectrodes, substantially as set forth.

6. The combination, with a telephone operated by the heating effects ofthe electric current, of an extra heating-battery in the line,substantially as set forth.

This specification signed and witnessed this 2d day of February, 1884.

SIGMUN D BERGMANN.

Witnesses:

WM. H. MEADOWCROFT, T. G. GREENE, J r.

